Both enzymesbelong to the lipid metabolism pathways and low level of PON1 hasbeen suggested a biomarker of DCM by Feig et al.13 Also the level of cartilage oligomeric matrix protein (COMP)was down-regulated in DCM patients similarly as in our previous study.43 Its reduced expression was observed in the hearttissues of DCM patients.44 Here, COMP is linked to familial dilated cardiomyopathy.